1. Field of the Invention
The present invention generally relates to an optical imaging lens set and an electronic device which includes such optical imaging lens set. Specifically speaking, the present invention is directed to an optical imaging lens set with shorter length and an electronic device which includes such optical imaging lens set.
2. Description of the Prior Art
In recent years, the popularity of mobile phones and digital cameras makes photography modules (including optical imaging lens set, holder and sensor, etc) well developed. Mobile phones and digital cameras become lighter and thinner, so the miniaturization demands of photography modules get higher and higher. As the charge coupled device (CCD) or complementary metal-oxide semiconductor (CMOS) technologies advance, the size of the photography modules can be shrunk too, but these photography modules still need to maintain good imaging quality.
As the requirements of good imaging quality increase, and the conventional optical imaging lens set of four lens element can hardly satisfy these requirements, a novel optical imaging lens set with small total length and good imaging quality is needed. U.S. Pat. Nos. 7,920,340, 7,660,049 and 7,848,032 disclose an optical imaging lens set of four lens elements respectively, and all of the total length (the distance between the first object surface of the first lens element to an image plane) of the optical imaging lens sets are over than 7 mm. The size of the optical imaging lens set is too big to satisfy the specification requirements of consumer electronics products.
Therefore, how to reduce the total length of a photographic device, but still maintain good optical performance, is an important research objective.